It is a longstanding idea that cognitive processing is subjectively costly: All else being equal, people will choose strategies or actions that minimize cognitive demands. This principle has been presumed to explain a wide array of decision-making phenomena, but has been subjected to surprisingly little direct experimental scrutiny. In recent work, we have gone some distance toward rectifying this, providing the first direct evidence for cognitive demand avoidance. Our initial behavioral findings link cognitive costs to demands on executive function or controlled information processing. Consistent with this, we have obtained neuroimaging results that tie cognitive costs to cortical areas centrally involved in executive control. In the present application, our objective is to build on this initial foundation constructing a fuller account of the role that control costs play in decision making, and of the relevant neural processes. The proposed experiments employ behavioral, neuroimaging and genetic techniques to pursue three specific aims: 1) We aim to evaluate the broader decision-making ramifications of control costs. Using an individual-differences approach, we propose to test for the involvement of control costs in two particularly important areas: A. Research on intertemporal choice has suggested a role for 'self-control' in resisting the temptation of immediate rewards. We aim to test the hypothesis that such forbearance carries control costs, potentially explaining why self-control in intertemporal choice is prone to occasional failure. B. Heuristic use in decision making has been proposed to arise from an effort-minimization principle. We propose to evaluate this hypothesis, by testing for a correlation between heuristic use and cognitive demand avoidance. 2) We aim to further probe the neural foundations of control costs. In particular, we will investigate the relationship between control costs and two key findings from previous work: A. Previous research has revealed a central role for dopamine in determining willingness to exert physical effort. Using a behavioral-genetic approach, we aim to investigate whether dopaminergic function plays a related role in the case of cognitive effort. B. Neuroimaging research has revealed that cortical areas supporting cognitive control operate alongside a 'default mode network.' Having linked control-cost computations with the control-related areas, we propose new neuroimaging work aimed at investigating the potential involvement of the default network in shaping cost-based decision making. 3) We aim to test a novel economic model of cost-sensitive decision making based on economic labor supply theory, a formal framework originally developed to account for effort allocation in labor markets. Initial experiments suggest that labor supply theory may provide a powerful tool for understanding the role of control costs in reward-based decision making. We propose to extend this initial work to address two outstanding questions: A. Does cognitive demand avoidance arise from a purely reactive mechanism, or does decision making actively anticipate demands for control? B. Can the labor-supply model account for shifts in control allocation over time, including so-called 'ego-depletion' effects? PUBLIC HEALTH RELEVANCE: The proposed work addresses a fundamental aspect of the cost-benefit analyses that underlie human decision making: cognitive demand avoidance. A tendency to avoid demands for mental effort has been proposed to explain a very wide array of decision-making phenomena, ranging from strategy selection in arithmetic to racial prejudice, and exaggerations of this bias have been hypothesized to underlie mental fatigue in depression and other illnesses. The proposed work aims to shed new light on the behavioral principles, the genetic determinants, and neural mechanisms underlying cognitive demand avoidance in decision making.